NEW YORK, Sept 12 (Reuters) - U.S. stocks gained on
Wednesday after a top German court gave a green light for the
country to ratify Europe's new bailout fund and before a Federal
Reserve decision on Thursday about injecting more stimulus into
the economy.

Stocks bounced in the early going after the German
Constitutional Court gave a green light for the new euro zone
rescue fund to go ahead, which will allow the European Central
Bank to buy sovereign bonds in an effort to lower interest rates
and boost economic growth.

But investors quickly shifted attention to the Fed, which
began a two-day policy meeting on Wednesday and is expected to
announce on Thursday whether it will introduce more monetary
easing.

"We are chipping away all these negative concerns of
investors," said Craig W. Johnson, market strategist at Piper
Jaffray. "The market is going to continue to move higher."

The S&P 500 index has advanced more than 9 percent since the
start of June on hopes for global central bank stimulus. But the
index has been unable to significantly pierce the 1,438-1,440
level, seen as a significant resistance point.

Apple Inc rose 1 percent to $667.50 after it
unveiled its iPhone 5. It has a larger 4-inch "retina" display,
ability to surf a high-speed 4G LTE network, and is 20 percent
lighter than the previous iPhone 4S. The introduction of the new
iPhone comes as Apple tries to fend off competition that has
reached fever-pitch.

The Dow Jones industrial average was up 26.14 points,
or 0.20 percent, at 13,349.50. The Standard & Poor's 500 Index
was up 4.15 points, or 0.29 percent, at 1,437.71. The
Nasdaq Composite Index was up 10.16 points, or 0.33
percent, at 3,114.69.

Facebook Inc jumped 6 percent to $20.64 after Chief
Executive Mark Zuckerberg hinted at new growth areas from mobile
to search in his first major public appearance since the No. 1
social network's rocky IPO in May.

Ford Motor's stock was up 0.7 percent and traded at
$10.22, after the company's board of directors decided to
discuss this week a succession plan for Chief Executive Alan
Mulally, who is expected to retire by the end of 2013, Bloomberg
reported on Tuesday, citing a person familiar with the matter.

Chesapeake Energy slipped 1 percent to $19.88 after
the company said it is selling $6.9 billion in gas fields and
pipelines, with most of its assets in the Permian Basin being
sold to Royal Dutch Shell Plc and Chevron Corp,
as well as most of its remaining infrastructure network.